a few tips on price control in landscaping

1. Ask yourself what you know about the landscaper's work (see my articles on "the landscaping jungle" and "common errors of landscapers and homeowners" for more on this).  It turns out that fees are not in any way a guarantor of skill.  Do your homework before hiring a landscaper.

2. Particularly at the "high end", it is customary for homeowners to write one big check for materials and services without knowing where the money is going.  This is a mistake.  Ask for a breakdown of charges for all materials and services.

3. If you have regular employees or subcontractors you like for landscape maintenance, hardscape work, etc.-- you may want to look for a landscaper who's willing to work with your subcontractors, rather than bringing in their own crew.

Services:
Upscale residential landscapers and many commercial companies with crews will charge $40-60/ "man-hour", yet workers are likely to see only $10 per hour of that.  Be aware that companies willing to offer bids upfront generally make their bids so high that they are sure to make a good profit.

For example, a homeowner I know who pays an astronomical fee for landscaping by a company retained by his HOA, recently needed to have some shrubs removed.  The HOA's company gave him a bid of $610; as he remarked, "I could go to Hawaii for that!"  A subcontractor we knew who charged $30/hr would have done the job in five hours.  The homeowner got a buddy to help him and did the work himself in three hours.

You may find that you pay significantly less for the same work when you deal with an independent subcontractor who simply gives his or her best guesstimate, then charges by the hour.  In addition, you have the satisfaction of knowing that the worker receives fair payment for his or her work.
In addition, the people who employ landscaping crews often do not provide good training or supervision, and then do not take responsibility when things are done incorrectly.
The one advantage of hiring a company with a crew is insurance coverage- IF it exists.  Determine whether the landscaper is insured, and whether the crew is covered by that insurance. To find out if someone is insured for landscaping or other contracting work, check with the WA Dept of Labor and Industries.

The reality of landscaping in the state of Washington is that state requirements for licensure and insurance are so expensive that the vast majority of gardeners and landscapers do not comply.  As the rules are so odd and so poorly communicated by government agencies, some very upstanding landscapers may work illegally for years, unaware of the insurance and licensing requirements. As a homeowner, your principal concern is to have quality work done with a minimum of damage.  Unfortunately, possession of a landscaping license in WA does not in any way indicate experience, training, competence, or oversight.  However, it does at least indicate insurance coverage in the event of damage so obvious and immediately identifiable that it is possible for you to pursue redress.

Materials:

Landscapers do not routinely have access to wholesale prices, as most growers require huge volumes; only quite large jobs (hundreds of plants) will be likely to involve wholesale purchases.

For plants and materials, it is normal for landscapers to receive a discount from their source (typically 15% on plants from retail nurseries), and then sell the materials to you at the same price you would pay if you made the purchase directly.
This is fair, as the alternative would be to charge you for time spent shopping and transporting the materials to your property.  Also, your landscaper may add a surcharge to items purchased from a source (like home Depot) that does not extend discounts.
However, beware of blanket charges that are not itemized.  You need to know exactly what plants and equipment you have purchased.  Make comparisons and make sure that you are not paying significantly more than you would if you bought the items yourself.
Your landscaper should be willing to give you an itemized list of plants with name, pot size, price, and source indicated for each.  They should also give you a list of any and all hardscaping materials used, with quantities, sizes, prices, and sources indicated. (In addition, I give homeowners descriptions in writing of all their new plants, with expected size, care requirements, etc.)
Some landscapers may want at least partial payment for plants and other materials upfront.  That is fair, but make sure you have appropriate documentation (a receipt) and at least by the end of the project an itemized list.